A number of issued U.S. patents of the present inventors, such as U.S. Pat. Nos. 7,178,353 B2, 7,415,835 and 7,765,820 disclose and claim different aspects of a unique methodology for control of the temperature of a thermal load. This methodology has generically been termed “Transfer Direct of Saturated Fluids” (usually abbreviated to TDSF) to identify in summary fashion that a two phase medium is not only temperature controlled but is itself in direct thermal contact with the thermal load. It also indicates that different states of the media are employed, varying from pure gas in an initial state through an intermediate range in which gas and liquid phases are mixed to provide a controllable temperature and pressure, and perhaps transitioning to pure liquid or gas phases under limiting conditions. The mixture of phases in the medium are varied in temperature and pressure so as to control the temperature of the load throughout a predetermined desired range without using an intermediate separate thermal transfer medium.
This technology was introduced initially to meet the precise temperature cycling and control requirements imposed in the semiconductor industry, where different process steps might require establishment of a succession of temperature levels at rapid speeds, often undertaking further exchanges of thermal energy as the process steps are effected. The use of the refrigerant itself in a direct thermal transfer with a load introduces specific problems in assuring control and stability, because of the phase changes that can take place as refrigerant temperature and pressure conditions are varied. Such problems are addressed and met in accordance with the method and apparatus patents referenced above.
The TDSF method and apparatus offer particular advantages for control of temperature within a chosen broad range, including flexibility in effecting the needed precision as to temperature, since the mixture of different phases of the refrigerant can be manipulated with versatility. The TDSF approach also facilitates the storage and manipulation of the internal energy in the different phases. When undertaking different modes of operation in these systems, multiple fluid paths exist in which single phase flows, and two-phase flows are separately established under controlled conditions. This enables thermal energy to be exchanged, stored and utilized in a variety of ways, and applicants disclose herein a multiplicity of ways providing novel systems and methods using such characteristics to advantage for effecting temperature control using thermal energy.